FSK避障雷达的APFFT测距及误差补偿

由于频移键控(Frequency-Shift Keying,FSK)体制避障雷达在动目标分辨与测量上的明显优势，基于FSK体制避障雷达系统的基本原理和结构，通过Matlab建立了测量系统与信号模型，使用全相位快速傅里叶变换（All-phase Fast Fourier Transformation，APFFT)算法进行了相关测量仿真和测量参数计算。通过对不同条件下的仿真结果分析，得出了测量结果误差产生的原因，并提出了相应的误差补偿方法，大大降低了测量误差，使得相对误差降低至0.1%以下。另外，还对多目标的分辨与测量进行了仿真。     

Quality disclosure in the presence of strategic consumers

Consider a market for short-life products, such as smartphones, where a firm and consumers have asymmetric quality information, the firm sells products in two periods, and consumers make purchase decisions strategically. We investigate when a firm should disclose quality and the interaction between consumers' strategic behavior and the firm's disclosure behavior. We obtain several findings. First, regardless of whether consumers have low or high patience, the firm should disclose quality information if product quality is high and conceal it if product quality is low. However, for products with moderate quality levels, the firm will disclose more quality information to consumers with relatively high or low patience levels than when consumer patience is moderate. Second, firms will disclose less information when consumers behave strategically than when they are myopic. Third, when concealing quality information is an equilibrium, product prices are affected only by disclosure costs and independent of true product quality. Finally, the firm can benefit from consumers' strategic behavior and a higher disclosure cost, but greater patience might be detrimental to consumer surplus and social welfare.     

Survival of the fittest: understanding the effectiveness of update speed in the ecosystem of software platforms

The ecosystem of software platforms is emerging as a dominant model for software-based services. Following the trend of open innovation, platforms extend product boundaries by encouraging many complementary apps to join them and organize an innovation ecosystem to satisfy the needs of heterogeneous users. In such innovation ecosystems, apps update and evolve continuously. Considering the ubiquitous nature of software updates, scholars have examined the impact of updates on the diffusion and market performance of focal software. However, few studies examined the moderators for the effectiveness of update speed. Apps, like organisms, do not exist in a vacuum. The success of one app depends not just on its own efforts but also on its interaction with other innovations in the ecosystem. Informed by the ecology theories, this study theorizes how the effectiveness of app update speed is influenced by ecological factors. Using longitudinal data about apps in a browser platform, we obtain several important insights. First, update speed has a significant positive effect on app performance. Second, frequent platform update and intraspecific competition weaken the effectiveness of update speed. Third, interspecific mutualism and developer capability strengthen the effectiveness of update speed. This study contributes by advancing the overall understanding of value software updates as well as providing novel insights about the interdependence in innovation ecosystems.     

基于联合分析法的快时尚服装消费偏好研究——来自太原市的证据

为解决快时尚品牌在二线城市的发展困境，以太原市264位快时尚服装购买者为样本，运用联合分析法从产品质量、时尚程度、服务水平三个方面构建快时尚服装消费偏好模型，并运用K-means聚类进行市场细分。结果表明，产品质量是影响太原市等二线城市消费者最为关键的因素；女性消费者更偏好时尚性和质量，男性则偏好产品的服务；在太原等二线城市快时尚服装本质是服装领域的“快消品”。据此，为快时尚品牌在太原市场的经营发展提出营销建议。     

Pricing VIX options with volatility clustering

We investigate the valuation of volatility index (VIX) options by developing a model with a self-exciting Hawkes process that allows for clustering in the VIX. In the proposed framework, we find semianalytical expressions for the characteristic function and forward characteristic function, and then we solve the pricing problem of standard-start and forward-start options via the fast Fourier transform. The empirical results provide evidence to support the significance of accounting for volatility clustering when pricing VIX options.     

星载AIS信号的频偏估计

星载自动识别系统（AIS）中信号存在严重的多普勒频偏，影响信号的正确解调，而传统的基于快速傅里叶变换（FFT）的频偏估计算法其估计范围无法满足需要。为此，提出了一种改进的自相关-FFT频偏估计算法，通过构造辅助函数以确定信号频偏的正负号，在此基础上对基于FFT的频偏估计算法进行改进，从而扩大频偏估计范围，实现对大的多普勒频移的估计。仿真和实验结果均表明，改进算法的频偏估计范围扩大为原来的2倍，具有很高的估计精度，十分接近修正后的克拉美罗界，且算法简单、易于实现。     

欧盟重型车排放法规研究

我国已成为重型汽车的生产和消费大国。如何实现我国空气质量目标,降低重型汽车排放的研究尤为紧迫。本文对最新的欧盟重型汽车排放法规主要技术内容及其发展、测试方法和测试设备的新要求进行了简要阐述,希望能对我国相关减排领域的标准化工作开展提供一些帮助。     

一种可快速编码的QC-LDPC码构造新方法

为解决LDPC码的编码复杂度问题,使其更易于硬件实现,提出了一种可快速编码的准 循环LDPC码构造方法。该方法以基于循环置换矩阵的准循环LDPC码为基础,通过适当的打孔 和行置换操作,使构造码的校验矩阵具有准双对角线结构,可利用校验矩阵直接进行快速编 码,有效降低了LDPC码的编码复杂度。仿真结果表明,与IEEE 802.16e中的LDPC码相比,新 方法构造的LDPC码在低编码复杂度的基础上获得了更好的纠错性能。     

卷烟滤嘴两种生产储运系统比较

在技术改造过程中,为了便于设备选型,对快速固化连接装置和自动化立体库这两种卷烟滤嘴棒储运系统进行了反复的考察和论证,认为这两种方式都能够在滤嘴棒成型机和发射机之间起到连接、储存、缓冲作用,但自动化立体库把物流技术、计算机管理和控制技术、网络技术、信息技术、数据库等有机结合起来,自动化、信息化程度高;储存量大,储存时间长,更易满足生产工艺要求;投资较少;生产组织灵活性高。     

恒源煤矿45采区液压支架集中拆装硐室研究及实践

皖北煤电集团公司恒源煤矿通过施工井下采区综采液压支架集中拆除硐室,安装风动行车,减轻了员工劳动强度,提高了施工的安全性,加快了施工速度,提高了功效,减少了综采液压支架安装拆除准备及施工工期,避免了工作面回采过液压支架安装硐室及煤柱回收过拆除硐室,创新了中小型矿井安装拆除液压支架新模式。